This invention relates to an ink ribbon feed mechanism for use with typewriters, calculating machines or other office machines and, more particularly, to such ink ribbon feed mechanism wherein the ink ribbon take-up or wind-up direction may be automatically reversed in dependence upon completion of take-up of the ink ribbon from one spool to the other spool, as sensed by sensors, said spools being mounted separately on a pair of spool shafts.
The ink ribbon feed mechanism of the above type has been known in the art. In a representative mechanism of this kind, reversal of take-up direction for the ink ribbon is sensed by a sensor, and the reverse mechanism is moved from one to the other position by the medium of a connecting member for selecting the altered engaging state of a pair of feed pawls relative to sprocket wheels that are mounted on a pair of spool shafts. However, in this kind of ink ribbon feed mechanism, there are problems with reliability of the reverse mechanism which can become locked at an intermediate position between two positions, whereby the smooth reversal of the ink ribbon take-up direction may be impeded.